Connector of the insulation-perforating type for a suspended electrical system

ABSTRACT

A connector of the insulation-perforating type for a suspended electrical system comprises conductive means for cutting an insulating covering of an insulated supply cable in order to connect an electrical device electrically to an uncovered portion of the supply cable, and an insulating structure for enclosing the conductive means, in which the insulating structure includes a first insulating element which can be closed around the supply cable in a non-reversible manner in order to protect the uncovered portion from manual contact, and a second insulating element which can be connected to the electrical device and which can be joined reversibly to the first insulating element, the first insulating element comprising means for preventing sliding along the supply cable.

The present invention relates to a connector of theinsulation-perforating type for a suspended electrical system.

Suspended electrical systems (or cable systems) are constituted byelectrical devices (typically lighting devices) supported and suppliedby insulated supply cables stretched, for example, between two walls.The devices are connected electrically to each supply cable by means ofsuitable insulation-perforating connectors.

Known connectors are generally constituted by an insulating body whichis closed around a portion of the supply cable and in a side portion ofwhich a free end of an insulated branch cable of the electrical deviceis inserted. A metal blade is forced into a slot in the insulating bodyso as to cut an insulating covering of the supply cable and of thebranch cable and thus to establish an electrical contact between the twocables; the slot in which the metal blade is inserted is then covered byan insulating protection element which can be reopened.

A disadvantage of known connectors is that they can easily be opened inorder to be moved to a different position along the supply cable. Inthis situation, the portion of the supply cable in which the connectorwas previously positioned is not insulated because its covering has beencut by the metal blade. This creates a dangerous situation and a seriousrisk in the event of accidental contact with the supply cable.

The object of the present invention is to overcome the above-mentioneddrawbacks. To achieve this object, a connector as described in the firstclaim is proposed.

In short, a connector of the insulation-perforating type for a suspendedelectrical system is provided and comprises conductive means for cuttingan insulating covering of an insulated supply cable in order to connectan electrical device electrically to an uncovered portion of the supplycable, and an insulating structure for enclosing the conductive means,the insulating structure including a first insulating element which canbe closed around the supply cable in a non-reversible manner in order toprotect the uncovered portion from manual contact, and a secondinsulating element which can be connected to the electrical device andwhich can be joined reversibly to the first insulating element, thefirst insulating element comprising means for preventing sliding alongthe supply cable.

An electrical device comprising the connector, a suspended electricalsystem comprising the device, and a corresponding connection method arealso proposed.

Further characteristics and the advantages of the connector according tothe invention will become clear from the following description of apreferred embodiment thereof, given by way of non-limiting example, withreference to the appended drawings, in which

FIG. 1 shows a suspended electrical system in which the connector of thepresent invention can be used,

FIG. 2 is a view of the connector with parts separated,

FIG. 3 shows an accessory used for the assembly of the connector,

FIG. 4 shows a variant of the connector.

With reference in particular to FIG. 1, a suspended electrical system100 is formed by two parallel cable structures 105 a and 105 b which arestretched horizontally between two walls (not shown in the drawing).Each cable structure 105 a, 105 b includes two supply cables, 110 a, 115a and 110 b, 115 b, respectively. Each of the cables 110 a, 115 a, 110b, 115 b is supplied at low voltage, for example, at between 110V and240V, and is covered by a double insulation sheath. Support cables 120 aand 120 b, also covered by a double insulation sheath, are disposedbetween the supply cables 110 a and 115 a and between the supply cables110 a and 115 b, respectively.

Three electrical devices 125 a, 125 b, 125 c, for example, three lamps,are connected between the cable structures 105 a and 105 b. The lamps125 a- 125 c are supported mechanically by the support cables 120 a, 120b and each is connected electrically to one of the supply cables 110 a,115 a and to one of the supply cables 110 b, 115 b, in a manner suchthat it can be lit separately.

The lamp 125 a (similar remarks apply to the other lamps 125 b- 125 c)is constituted by a toroidal load-bearing element 130, made, forexample, of metal, on which is mounted a halogen light 135 orientableabout an axis parallel to the cable structures 105 a, 105 b. The lamp125 a is connected electrically to the supply cable 115 a and to thesupply cable 115 b by means of connectors indicated 140 a and 140 b,respectively.

Similar remarks apply if the cable structures are stretched between aceiling and a floor, if each cable structure includes a different numberof supply cables (or even only one), if a different number of insulatingsheaths (or even only one) is provided, if a different supply voltage isused, if no support cable is provided (with the electrical devicessupported directly by the supply cables), if the lamps have a differentstructure, if other electrical devices such as loudspeakers, fans, smokedetectors, infra-red switches, are used, etc.

With reference now to FIG. 2, the connector 140 a (similar remarks applyto the other connector 140 b) has an insulating structure (made, forexample, of plastics material) formed by a fixed element 203 f and by aremovable element 203 r. The insulating structure 203 f, 203 r enclosestwo metal blades 206 f and 206 r (made, for example, of tinned copperalloy). The connector 140 a is of the insulation-perforating (or“self-stripping”) type in which the metal blade 206 f cuts an insulatingcovering of the supply cable 115 a in order to make electrical contactwith an uncovered portion 209 thereof; similarly, the metal blade 206 rcuts an insulating covering of a branch cable 212 of the lamp 125 a inorder to make electrical contact with an uncovered portion thereof.

As described in detail below, the insulating element 203 f is closedaround the supply cable 115 a (and the metal blade 206 f) in anon-reversible manner; the insulating element 203 f is clamped on thesupply cable 115 a so as not to be able to slide along it. Thisinsulating element 203 f protects the uncovered portion 209 from anymanual contact (either direct or via the metal blade 206 f). Theinsulating element 203 r houses a free end of the branch cable 212including the uncovered portion which is connected to the metal blade206 r. The insulating element 203 r is joined to the insulating element203 f in a manner such that the metal blade 206 r comes into contactwith the metal blade 206 f, connecting the lamp 125 a electrically tothe supply cable 115 a; this operation is reversible so that theinsulating element 203 r (and hence also the metal blade 206 r fixedthereto and connected to the branch cable 212) can be removed,disconnecting the lamp 125 a from the supply cable 115 a.

Similar remarks apply if the branch cable extends through the insulatingstructure in order to supply two lights in parallel, if the lamp isconnected to the metal blade in a different manner, or if a single metalblade or other equivalent conductive means are provided.

The connector according to the present invention allows the electricaldevice to be removed from the suspended system without any risk. Theinsulating element 203 f in fact always remains closed around theuncovered portion 209 of the supply cable 115 a and can be neitherremoved nor displaced from this position; the removal of the electricaldevice does not therefore uncover the portion of the supply cable inwhich the insulating covering has been cut, so that any risk ofaccidental contact with live elements is prevented. The fact that theinsulating element 203 f cannot slide along the supply cable 115 a isalso particularly advantageous during the installation of the lamp 125 aif the supply cable 115 a is not arranged horizontally, since theinsulating element 203 f is prevented from sliding downwards.

The insulating element 203 f which has remained closed around the supplycable 115 a can also be reused (but not removed) for connecting otherelectrical devices, allowing the structure of the suspended electricalsystem to be modified extremely easily but with maximum safety. Forexample, a series of pairs of insulating elements may be provided,suitably spaced along two cable structures, so as to render thearrangement of the various electrical devices very practical andflexible.

In the embodiment shown in the drawing, the insulating element 203 f isformed by a base 215 which is closed at the top (that is, along a minortransverse axis of the cable structure 105 a) by a cover 218. The base215 is constituted by a disk 221 in the top of which there are threelongitudinal channels 224, 225 and 226 which house the supply cable 110a, the support cable 120 a, and the supply cable 115 a, respectively. Asharpened wall 227, which is shaped as a cutting and opening-outfinger-nail (or other equivalent means) is disposed between the channel225 and the channel 226. A resilient (straight) wall 230 a and aresilient (arcuate) wall 230 b extend upwards from outer side edges ofthe channel 224 and of the channel 226, respectively. Each resilientwall 230 a, 230 b has an upper engagement tooth 233 a, 233 b and a lowerengagement tooth 234 a, 234 b. One or more cable-gripping ribs 236 areformed on an inner surface of the resilient wall 230 a.

The cover 218 is constituted by a cylinder 239 having a lower cavity inwhich there are two lateral channels 242 a and 242 b, each having abearing surface mating with the engagement teeth 233 a, 234 a and 233 b,234 b, respectively. Along a lower edge of the cylinder 239 there aretwo notches 245 (only one of which is shown in the drawing)corresponding to the cable structure 105 a. A tower 248 extendingupwards from an upper end of the cylinder 239 has longitudinal grooves250 formed on a side surface; a slot 251 extends through the tower 248as far as the lower cavity of the cylinder 239. Two engagement teeth 254a and 254 b are disposed on the upper end of the cylinder 239 beside thetower 248 in symmetrical positions relative thereto.

The metal blade 206 f has a downwardly-facing, U-shaped opening 257 land an upwardly-facing U-shaped opening 257 h; the openings 257 h and257 l are not aligned with one another and are thus arranged on thelongitudinal axes of the connector 140 a and of the supply cable 115 a(or of the supply cable 120 a if the metal blade 206 f is rotatedthrough 180° relative to the longitudinal axis of the connector),respectively. A clamping hole 260 is formed in the metal blade 206 fbeneath the opening 257 h. The metal blade 206 f is inserted into thecover 218 from below until the opening 257 h is fitted in a lowerportion of the slot 251 and is locked in this position by a punchingburr of the hole 260 which interferes with an inner lateral surface ofthe slot 251. The opening 257 l projects downwards from the slot 251into the lower cavity of the cylinder 239.

The insulating element 203 r is formed by an inner cylinder 263 i and anouter cylinder 263 e. The inner cylinder 263 i has a lower cavity 267having ribs 266 complementary to the grooves 250. A slot 269 is formedin an upper end of the inner cylinder 263 i for access to the cavity267. On a lateral surface of the inner cylinder 263 i there are twoprojections 272 a and 272 b disposed in the vicinity of a lower rim ofthe inner cylinder 263 i and two longitudinal strips 273 (of which onlyone is shown in the drawing). Two outer resilient tabs extend upwardlyfrom the lower rim of the inner cylinder 263 i, and each terminates in abutton 274 a, 274 b; two recesses 275 a and 275 b complementary to theengagement teeth 254 a and 254 b, respectively, are formed beneath thecorresponding buttons 274 a and 274 b.

The outer cylinder 263 e has a lower cavity (matching the inner cylinder263 i) in which there are two lateral grooves 276 a and 276 b,complementary to the corresponding projections 272 a and 272 b andlongitudinal grooves 277 (having self-centring lead-in openings)complementary to the strips 273. On a lateral wall of the outer cylinder263 e, there are two holes 278 a and 278 b for the buttons and thecorresponding engagement teeth 274 a, 254 a and 274 b, 254 b,respectively. Two notches 281 (of which only one is shown in thedrawing), corresponding to the cable structure 105 a, are formed along alower rim of the outer cylinder 263 e. In the vicinity of an upper endof the outer cylinder 263 e there is a blind hole 284 for the free endof the branch cable 212 which has an intermediate portion (not shown inthe drawing) in communication with the lower cavity of the outercylinder 263 a.

The metal blade 206 r is T-shaped with a main body 287 from which twoupper arms 290 a and 290 b extend. Between the two arms 290 a and 290 bthere is an upwardly-facing U-shaped opening 293.

In an operative condition, the base 215 is placed against the cablestructure 105 a in the position in which the lamp 125 a is to beinstalled. The sharpened wall 227 enables the supply cable 115 a to beseparated automatically from the support cable 120 a without the needfor any preliminary operation to cut and open out the cable structure105 a.

The cover 218 is then placed against the base 215 and is forced againstit until the upper engagement teeth 233 a, 233 b are snap-fitted in thegrooves 242 a, 242 b. The different shapes of the resilient walls 230 aand 230 b facilitate the correct positioning of the cover 218 relativeto the base 215 (similar remarks supply if the base and the cover have adifferent asymmetric shape) The cover 218 is thus temporarily engaged onthe base 215 extremely easily. The cover 218 and the base 215 do nottherefore need to be held together during the subsequent operations(described below) to assemble the connector; the lamp 125 a can thus beinstalled easily and safely, even in unstable conditions.

With reference now to FIG. 3 (elements already shown in FIG. 2 areidentified by the same reference numerals) the cover 218 is fixedfinally to the base 215 with the use of an assembly accessory 305. Theaccessory 305 is constituted by a cylinder 310 in which there is acavity 315 complementary to a lateral surface of the insulating element203 f and closed by an end portion 320; along a free rim of the cylinder310 there are two notches 325 (of which only one is shown in thedrawing) corresponding to the cable structure 105 a. Two holes 330 a and330 b are also formed in the end portion 320 for the engagement teeth254 a and 254 b of the cover 218, respectively.

The accessory 305 is fitted on the cover 218 until an end of the tower248 abuts the end portion 320. If the base 215 and the accessory 305(which contains the cover 218) are pressed together, for example, bypincers, the lower engagement teeth of the base 215 (indicated 234 a,234 b in FIG. 2) are snap-fitted in the corresponding grooves of thecover 218, clamping the cover 218 finally on the base 215. Theengagement teeth 254 a, 254 b are forced into the holes 330 a, 330 b,keeping the accessory 305 connected to the insulating element 203 f. Theaccessory 305 is then removed manually by being slipped off theinsulating element 203 f (simply by pulling).

The accessory 305 described above facilitates the assembly of theinsulating element 203 f and ensures that the coupling between the base215 and the cover 218 take place in the correct direction so as toprevent any damage thereto. Moreover, if the electrical device should beremoved, the accessory 305 can be mounted on the insulating element 203f (being held in position by the engagement teeth 254 a, 254 b forcedinto the holes 330 a, 330 b), improving the appearance of the suspendedelectrical system.

With further reference to FIG. 2, the clamping of the cover 218 on thebase 215 is not reversible since the engagement teeth 234 a, 234 b arenot accessible from the exterior so that it is not possible to open theinsulating element 203 f by a non-destructive method. During theabove-described operation, the cable structure 105 a is forced into thenotches 245 and against the ribs 236 so as to prevent any sliding of theinsulating element 203 f along the cable structure 105 a. At the sametime, the opening 257 l bears against the supply cable 115 a and, whenthe cover 218 is forced against the base 215, the opening 257 l cuts theinsulating covering of the supply cable 115 a (with deformation ofplastics material which is disposed in suitable relief grooves, notshown in the drawing); an internal conductor of the supply cable 115 ais urged under pressure into the opening 257 l so as to be in electricalcontact with the metal blade 206 f. The metal blade 206 f is arrangedinside the insulating element 203 f. The limited dimensions of the slot251 prevent the metal blade 206 f from being touched from the exterior.Moreover, the height of the tower 248 and the width of the tower 248,together with the limited dimensions of the grooves 250, ensure that thedistance of the metal blade 206 f from any point accessible manuallyfrom the exterior (the air gap) is sufficiently large; this distance hasa value, for example, no less than 6.5 mm, such as to prevent anelectrical current due, for example, to air pollution (such as dust,moisture or the like) from accidentally being transmitted between themetal blade 206 f and a person's finger, so as to form a so-calledenhanced insulation.

The above-described structure is particularly simple and effective.Alternatively, the base and the cover are constituted by otherequivalent units (of different, possibly symmetrical shapes, and withouta sharpened wall), no system is provided for temporarily joining thecover to the base, the element is assembled without assemblyaccessories, the insulating element has other equivalent means forpreventing sliding along the cable structure, the engagement teeth areprovided on the cover and the corresponding grooves on the base, or pinswith conical heads inserted in corresponding holes or other equivalentsnap-closure means, non-removable screws (with unidirectional shearingor predetermined fracture), are used, etc.

The metal blade 206 r is fitted in the slot 269 from above until thearms 290 a, 290 b abut the upper end of the inner cylinder 263 i. Thefree end of the branch cable 212 is inserted fully into the blind hole284. The inner cylinder 263 i is fitted in the lower cavity of the outercylinder 263 e (guided by the strips 273 which slide along the grooves277) until the opening 293 bears against the branch cable 212. If theinner cylinder 263 i is forced into the outer cylinder 263 e, theopening 293 cuts the insulating covering of the branch cable 212 (withdeformation of plastics material which is disposed in suitable reliefgrooves, not shown in the drawing); an internal conductor of the branchcable 212 is urged under pressure into the opening 293 so as to be inelectrical contact with the metal blade 206 r. At the same time, theprojections 272 a, 272 b are inserted in the grooves 276 a, 276 b,snap-locking the inner cylinder 263 i irreversibly (whilst the buttons274 a, 274 b are inserted in the holes 278 a, 278 b).

In the above-described structure, the metal blade 206 r (once it iselectrically connected to the branch cable 212) is disposed inside theinsulating element 203 r; the fact that the metal blade 206 r is not astall as the inner cylinder 263 i and the presence of the ribs 266prevent the metal blade 206 r from being touched from the exterior andensure the correct air gap and the corresponding enhanced insulation.This characteristic further increases the safety of the connector 140 asince it prevents any accidental contact with the metal blade 206 rwhich could be particularly dangerous if another end of the lamp 125 awere connected to a live supply line. Moreover, the metal blade 206 r isirremovable and the branch cable 212 cannot be removed from theinsulating element 203 r, so that a particularly practical unit isformed. The above-described operations are performed in the factoryduring the assembly of the lamp 125 a although the possibility of theirbeing performed directly on the spot, immediately before the lamp 125 ais installed, is not excluded.

Moreover, the double structure of the insulating element 203 r isparticularly safe since it locks the metal blade 206 r in the insulatingelement 203 r absolutely irremovably.

Similar remarks apply if the metal blades have a different structure andare housed in cavities of different shapes in order to be protected frommanual contact and to ensure the correct air gap (or purely to beprotected from manual contact), if differently shaped inner and outerelements are used, if the two elements are joined together in anothermanner (possibly reversibly), if the outer element covers only theaccess slot in which the metal blade is inserted, etc. The connector ofthe present invention may in any case also be formed with the insulatingelement connected to the branch cable constituted by a single body, orwith a single metal blade connected to the branch cable and projectingfrom the corresponding insulating element. In this case, the insulatingelement closed around the supply cable has a narrow slot in which themetal blade is fitted. During the installation of the lamp, the metalblade cuts the supply cable so as to connect the branch cableelectrically thereto; when the insulating element connected to thebranch cable is removed, pulling with it the metal blade firmly fixedthereto, the uncovered portion of the supply cable remains protected bythe insulating element which is closed around it.

With further reference to the connector shown in the drawing, at thispoint the insulating element 203 r is fitted on and forced against theinsulating element 203 f (guided by the ribs 266 which slide along thegrooves 250); the engagement teeth 254 a, 254 b are fitted between theinner cylinder 263 i and the lateral wall of the outer cylinder 263 euntil they reach the recesses 275 a, 275 b and are snap-fitted in theholes 278 a, 278 b. At the same time, the main body 287 of the metalblade 206 r is fitted in the slot 251 and is thus fitted in the opening257 h of the metal blade 206 f (transversely relative thereto) so as toconnect the branch cable 212 of the lamp 125 a electrically to thesupply cable 115 a (similar remarks apply if the metal blade 206 f isfitted in the cavity which houses the metal blade 206 r). In thissituation, the metal blades 206 f, 206 r are completely enclosed by theinsulating structure 203 f, 203 r and are not accessible in any way fromthe exterior and thus ensure the correct air gap and the correspondingenhanced insulation. The insulating element 203 r can easily be removedby manually pressing the buttons 274 a, 274 b which urge the engagementteeth 254 a, 254 b inwards, releasing them from the holes 278 a, 278 b;at this point, it suffices to withdraw the insulating element 203 rwhich also pulls with it the metal blade 206 r firmly fixed thereto.

Similar remarks apply if the insulating elements are of another shape,if there is a different number of engagement teeth (or even only one),or if the teeth are formed on the element connected to the branch cable,if other equivalent resilient elements are provided, etc. This structureenables the insulating elements to be joined and separated in a verypractical and safe manner and can be mass-produced at low cost. Inparticular, the above-described buttons enable the engagement teeth tobe released from the corresponding holes without the use of any tools.Alternatively, the engagement teeth are released by the tip of ascrewdriver (without any buttons), other equivalent snap-closure meansare used, the insulating elements are joined together simply bypressure, by means of fixing screws, etc.

With further reference to FIG. 1, the insulating element 203 r of theconnector 140 a (similar remarks apply to the connector 140 b) forms anintegral part of the load-bearing structure 130 which supports the lamp125 a. This renders the installation of the lamp 125 a extremely quickand easy; in fact, once the insulating elements have been closed aroundthe cable structures 105 a and 105 b, it suffices to pull them apartslightly and to snap-connect the corresponding insulating elementsincluded in the load-bearing structure 130. Similar remarks apply if theinsulating elements included in the load-bearing structure of the lampare disposed outside the two cable structures (so that they have to bemoved towards one another during the installation of the lamp) if theconnectors are covered by a protective screen of the lamp, etc. Theconnector of the present invention may also be used in other electricaldevices, possibly without being an integral part of their load-bearingstructure (but simply enclosed therein).

In a different embodiment of the present invention, as shown in FIG. 4,(elements structurally and functionally similar to those shown in FIG. 2are identified by the same reference numerals and their explanation isomitted for simplicity of description) a connector 400 is provided inwhich the insulating element 203 f is constituted by two half-shells 405a, 405 b joined together along a major transverse axis of the cablestructure 105 a. Respective channels 410 a and 410 b are defined in thehalf shells 405 a and 405 b; when the half-shells 405 a, 405 b arejoined together, the channels 410 a, 410 b define a tubular structurewhich houses the supply cable 115 a (or alternatively the supply cable110 a). Respective grooves 415 a, 415 b are formed transversely relativeto the channels 410 a, 410 b. In addition to the U-shaped opening 257 h,the metal blade 206 f has a U-shaped opening 420 arranged transverselyrelative to the opening 257 h; the metal blade 206 f is fixed in thegroove 415 a of the half-shell 405 a (with the opening 420 facingoutwardly).

The insulating element 203 r is constituted by a single body in whichthe cavities 267, the holes 278 a, 278 b (for the engagement teeth 254a, 254 b disposed on a lateral surface of the insulating element 203 f)and the blind hole 284 are formed. Two further blind holes 425 a, 425 bare arranged parallel to the blind hole 284 on opposite sides thereof;each of the blind holes 425 a, 425 b defines, in the cavity 267, anundercut portion complementary to the respective arm 290 a, 290 b of themetal blade 206 r.

In an operative condition, the half-shell 405 a is placed against thesupply cable 115 a previously separated (for example, by a screwdriver)from the support cable 120 a. The half-shell 405 b is inserted betweenthe supply cable 115 a and the support cable 120 a. The insulatingelement 203 f is then snapped shut irreversibly around the supply cable115 a and the opening 420 simultaneously cuts the insulating covering ofthe supply cable 115 a.

The free end of the branch cable 212 is inserted fully into the blindhole 284. The metal blade 206 r is press-fitted in the cavity 267 frombelow (by means of a suitable tool) until it cuts the insulatingcovering of the branch cable 212; at the same time, each of the arms 290a, 290 b is snap-fitted in the corresponding undercut portion formed bythe respective blind hole 425 a, 425 b, locking the metal blade 206 rinside the cavity 267.

As in the previous embodiment, the insulating element 203 r is fitted onthe insulating element 203 f and the engagement teeth 254 a, 254 b aresnap-fitted in the holes 278 a, 278 b; at the same time, the main body287 of the metal blade 206 r is fitted in the opening 257 h of the metalblade 206 f. The insulating element 203 r can be withdrawn (pulling withit the metal blade 206 r firmly fixed thereto) simply by releasing theengagement teeth 254 a, 254 b from the holes 278 a, 278 b.

This structure is extremely compact and thus very advantageous for theconnection of electrical devices of limited size. Moreover, theinsulating element, which remains closed around the supply cable shouldthe electrical device be removed, is extremely small and does nottherefore adversely affect the appearance of the suspended electricalsystem as a whole. It should be noted, however, that the above-describedconnector cannot be used to support the electrical device on the cablestructures (but only for its electrical connection) and should thereforealways be housed inside the load-bearing structure thereof.

Naturally, in order to satisfy contingent and specific requirements, anexpert in the art may apply to the above-described connector manymodifications and variations all of which, however, are included withinthe scope of protection of the invention as defined by the followingclaims.

What is claimed is:
 1. A connector of the insulation-perforating typefor a suspended electrical system, comprising: a. conductive means forcutting an insulating covering of an insulated supply cable in order toconnect an electrical device electrically to an uncovered portion of thesupply cable, the conductive means comprising a first conductive elementconnected electrically to the uncovered portion of the supply cable anda second conductive element connected electrically to the electricaldevice, the first and the second conductive element being housed,respectively, in a first cavity of the first insulating element and in asecond cavity of the second conducting element, in order to be protectedfrom manual contact, one of the first conductive element and the secondconductive element being fitted in the corresponding cavity of the otherconductive element in order to contact the other conductive element;and, b. an insulating structure for enclosing the conductive means, theinsulating structure comprising a first insulating element which can beclosed around the supply cable in a non-reversible manner in order toprotect the uncovered portion from manual contact, and a secondinsulating element which can be connected to the electrical device andwhich can be joined reversibly to the first insulating element, thefirst insulating element comprising means for preventing sliding alongthe supply cable.
 2. A connector according to claim 1, in which adistance between each conductive element and any point accessiblemanually from the exterior is greater than an enhanced insulation value.3. A connector according to claim 1 or claim 2, in which the secondinsulating element includes an inner insulating element and an outerinsulating element, the second cavity being formed in the innerinsulating element, and in which the inner insulating element has afirst opening for access to the second cavity, the second conductiveelement being fitted in the second cavity through the first opening andthe outer insulating element being disposed around the first opening,and in which the outer insulating element has a second opening foraccess to the second conductive element for housing a free end of aninsulated branch cable of the electrical device, the second conductiveelement being suitable to cut an insulting covering of the branch cablein order to be connected electrically to an uncovered portion thereof.4. A connector according to claim 1 or claim 2 in which the insulatingstructure includes at least one engagement tooth and at least onecorresponding hole for snap-connecting the second insulating element tothe first insulating element and at least one resilient element which issuitable to be fitted in the at least one corresponding hole, the atleast one resilient element cooperating with the at least one engagementtooth in order to release the at least one engagement tooth manually forthe at least one hole.
 5. A connector according to claim 1 or claim 2 inwhich the first insulating element includes a first insulating unit anda second insulating unit which are joined together around the supplycable, first snap means for temporarily joining the second insulatingunit to the first insulating unit, and second snap means for finallyjoining the second insulating unit to the first insulating unit.
 6. Aconnector according to claim 5, in, which the supply cable is includedin a suspended cable structure, the first insulating unit comprisingcutting and opening-out means for separating the supply cable from aremaining portion of the cable structure in the vicinity of theuncovered portion.
 7. An electrical device for use in a suspendedelectrical system having a first cable structure and a second cablestructure each comprising at least one supply cable the electricaldevice being electrically connected to a supply cable of each cablestructure by means of the connector according to claim 1 or claim 2 andhaving a load-bearing structure comprising the second insulating elementof each connector for supporting the electrical device on the firstcable structure and on the second cable structure.
 8. A suspendedelectrical system comprising at least one electrical device according toclaim 7, and a first suspended cable structure and a second suspendedcable structure for supplying and supporting the at least one electricaldevice.
 9. A method of connecting an electrical device in a suspendedelectrical system employing the connector of claim 1, comprising thestep of cutting an insulating covering of an insulated supply cable byconductive means of a connector of the insulation-perforating type, themethod being characterized by the steps of: closing a first insulatingelement around the supply cable in a non-reversible manner in order toprotect an uncovered portion of the supply cable from manual contact,the first insulating element comprising means for preventing slidingalong the supply cable, connecting a second insulating element to theelectrical device, joining the second insulating element to the firstinsulating element in a reversible manner in order to connect theelectrical device electrically to an uncovered portion of the supplycable by the conductive means and to enclose the conductive means in thefirst insulating element and the second insulating element.
 10. Aconnector of the insulating-perforating type for a suspended electricalsystem comprising a conductive means for cutting an insulating coveringof an insulated supply cable in order to connect an electrical deviceelectrically to an uncovered portion of the supply cable, and aninsulating structure for enclosing the conductive means, the insulatingstructure comprising: a. a first insulating element which can be closedaround the supply cable in a non-reversible manner in order to protectthe uncovered portion from manual contact, the first insulating elementcomprising means for preventing sliding along the supply cable; and b. asecond insulating element which can be connected to the electricaldevice and which can be joined reversibly to the first insulatingelement, wherein the conductive means includes a first conductiveelement connected electrically to the uncovered portion of the supplycable and a second conductive element connected electrically to theelectrical device, the first conductive element being suitable tocontact the second conductive element and being housed in a cavity ofthe first insulating element in order to be protected from manualcontact.